The stock upper control arm is the typical light-gauge, stamped-out design. The Boss unit is equipped with a bit harder durometer bushing than the stock GT piece and is non-adjustable. The beefy piece from BMR is manufactured from thick steel-plate and is fully TIG-welded for unmatched rigidity. It features a much stiffer bushing and a double-adjustable 4130 chrome-moly stud that has left LH/RH threads so the center nut can be used to adjust the length when installed in the car. In addition, it has two front mounting points; the one shown is designed to correct the geometry of lowered cars.